The darn air pump was making so much noise I knew it was going to quit. It did and the service engine light came on. Amazing thing though, the car runs cooler and steady engine temp.

Where can I get one, and do I need it ? GM is killing me for a new one

 

You can just get rid of it, and it won't set a code (as long as you replace the fuse). You will have to block off the fittings on the exhaust manifolds though.
Or, I could sell you mine cheap off my 93.